Effusion cytology of EBV-associated lymphoma: a concise review

Epstein-Barr virus (EBV)-associated lymphomas can, on rare occasions, involve body cavities, making effusion cytology an important diagnostic tool. This mini-review explores the spectrum of EBV-related lymphomas that may be detected in serous fluids, including EBV-positive nodal T/NK-cell lymphoma (EBV + nT/NKCL), extranodal NK/T-cell lymphoma, primary effusion lymphoma, EBV-positive diffuse large B-cell lymphoma, and classic Hodgkin lymphoma. We present an index case of EBV + nT/NKCL with lymphomatous pleural effusion and discuss the cytologic features, differential diagnoses, and role of ancillary studies such as immunocytochemistry, EBER in situ hybridization, and molecular assays. Accurate diagnosis requires the integration of cytomorphologic, immunophenotypic, and molecular findings with clinical information to establish a definitive diagnosis and distinguish these aggressive lymphomas from reactive and non-hematologic mimics.